Re: [PATCH v15 10/10] arm64: Add IMA log information in kimage used for kexec

On 1/27/21 8:54 AM, Will Deacon wrote:

Hi Will,

On Fri, Jan 15, 2021 at 09:30:17AM -0800, Lakshmi Ramasubramanian wrote:

quoted

Address and size of the buffer containing the IMA measurement log need
to be passed from the current kernel to the next kernel on kexec.

Add address and size fields to "struct kimage_arch" for ARM64 platform
to hold the address and size of the IMA measurement log buffer.

Update CONFIG_KEXEC_FILE to select CONFIG_HAVE_IMA_KEXEC, if CONFIG_IMA
is enabled, to indicate that the IMA measurement log information is
present in the device tree for ARM64.

Co-developed-by: Prakhar Srivastava <redacted>
Signed-off-by: Prakhar Srivastava <redacted>
Signed-off-by: Lakshmi Ramasubramanian <redacted>
Reviewed-by: Thiago Jung Bauermann <redacted>
---
  arch/arm64/Kconfig             | 1 +
  arch/arm64/include/asm/kexec.h | 5 +++++
  2 files changed, 6 insertions(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1d466addb078..ea7f7fe3dccd 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -1094,6 +1094,7 @@ config KEXEC
  config KEXEC_FILE
  	bool "kexec file based system call"
  	select KEXEC_CORE
+	select HAVE_IMA_KEXEC if IMA
  	help
  	  This is new version of kexec system call. This system call is
  	  file based and takes file descriptors as system call argument

diff --git a/arch/arm64/include/asm/kexec.h b/arch/arm64/include/asm/kexec.h
index d24b527e8c00..2bd19ccb6c43 100644
--- a/arch/arm64/include/asm/kexec.h
+++ b/arch/arm64/include/asm/kexec.h

@@ -100,6 +100,11 @@ struct kimage_arch {
  	void *elf_headers;
  	unsigned long elf_headers_mem;
  	unsigned long elf_headers_sz;
+
+#ifdef CONFIG_IMA_KEXEC
+	phys_addr_t ima_buffer_addr;
+	size_t ima_buffer_size;
+#endif

Why do these need to be in the arch structure instead of 'struct kimage'?

Currently, only powerpc and, with this patch set, arm64 have support for 
carrying forward IMA measurement list across kexec system call. The 
above fields are used for tracking IMA measurement list.

Do you see a reason to move these fields to "struct kimage"?

thanks,
  -lakshmi

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